Ballast fluid

ABSTRACT

Waterborne vessels are ballasted using water containing dissolved metal salts such as potassium carbonate.

United States Patent 1111 3,568,619

[72] Inventor John P. Sloan,Jr. [56] References Cited Houston, Tex. UNITED STATES PATENTS QYJJ 2212 22 1969 3,318,278 5/1967 Huebotter 114/125 45] Patented Mar. 11,1971 FOREGN f T {73] Assignee Dresser Industries, Inc. 1,010,865 11/1965 Great Bntam 114/125 Dallas? Primary Examiner'lrygve M. Blix A ttorney- R0bei1'W. Mayer, Daniel Rubin, PeterJ Murphy, Frank s. Troidl, Roy L. VanWinkle, William E. Johnson, Jr. [54] and Roderick W. MacDonald [52] U.S.Cl. 7 114/125 [51] Int. Cl. ..B63b43/06 [50] Field of Search 114/125; ABSTRACT: waterborne vessels are ballasted using water containing dissolved metal salts such as potassium carbonate.

BALLAST FLUTE BACKGROUND OF THE INVENTION l-leretofore liquids have been employed for ballasting waterborne vessels such as cargo ships. Ballasting comprises introducing a relatively heavy material into a lower portion of the vessel, e.g., ballast tanks on the bottom of the vessel, thereby lowering the center of gravity of the vessel and any cargo therein. The ballast adds stability to the vessel particulariy when the vessel lists to one side. Ballasting also comprises pumping liquids such as fresh water and sea water from one tank to another as necessary to give the ship proper trim and heel. Liquid mud ballasts are not generally useful for trimming" a ship because its high viscosity and gel prevent it from being pumped easily and quickly.

The liquid mud ballasts employed heretofore have contained dispersed therein a particulate weighting material such as barite, gelling agents, deflocculents, and the like. Problems have been encountered, however, in that upon long standing of the ballast inthe ballast tanks, the particulate weighting agent tends to settle out of the ballast liquid and cake on the bottom of the ballast tank thereby rendering it extremely difficult, if not impossible, to remove all of the ballasting material from the ballast tank. Further, such liquids are subject to bacterial attack and can themselves cause corrosion of the ballast tanks.

Sea water is very easily pumped into and out from ballast tanks and is used extensively for trimming a ship. However, it has the disadvantages of being corrosive due to dissolved halide salts and of not having the desired high density.

The ballast fluid of this invention is essentially noncorrosive, has a higher density, and is also easily pumped into and out from ballast tanks, thereby being useful as both a fixed ballast and a trim ballast.

SUMMARY OF THE INVENTION According to this invention, a ballast liquid is provided which has substantial weight and therefore is effective in lowering the center of gravity of a vessel, but which does not contain suspended weighting particles, is substantially free from bacterial attack, and is substantially noncorrosive.

The ballasting liquid of this invention is a solution, not a dispersion, of certain metal salts as hereinafter described in detail, the metal salts having been dissolved in the water in amounts sufficient to give the resulting aqueous solution the desired high density. This resulting aqueous solution is the ballast liquid of this invention.

Therefore, according to this invention there is provided a method of ballasting a vessel by introducing into the ballast tanks of that vessel an effective ballasting amount of the aqueous solution just described.

Ballast tanks in this invention are to be considered broadly to cover any lower portion of a vessel which can be made to receive and hold a liquid for any desired length of time.

Accordingly, it is an object of this invention to provide a new and improved method of ballasting waterborne vessels.

Other aspects, objects and advantages of this invention will be apparent to those skilled in the art from this disclosure and the appended claims.

DETAlLED DESCRlPTlON OF THE INVENTION The ballasting method of this invention comprises introducing into the ballast tanks an effective ballasting amount (an amount sufficient to lower the center of gravity of the vessel) of a ballasting liquid formed from sweet water (as distinguished from salt water with substantial amounts of dissolved halide salts) which has dissolved therein sufficient amounts of one or more metal salts to give an aqueous solution having a density of from about 75 to about 125, preferably from about 75 to about lOO, pounds per cubic foot.

The salts used to obtain the ballast liquid of this invention include carbonates, silicates, chromates (including dichromates), sulfates (including alums), hydroxides, nitrates, and

nitrites of one or more of the alkali metals (particularly lithium, sodium, potassium, rubidium, and cesium), silver, lead, iron, cobalt, nickel, manganese, molybdenum, chromium, tungsten, vanadium, zirconium, and titanium. The metal salts used in preparing the ballast liquids of this invention must be soluble in water either alone or in combination with one or more other salts to give an aqueous solution with the required density.

Examples of suitable salts are potassium carbonate, sodium carbonate, sodium silicate, potassium silicate, sodium chromate, potassium chromate, sodium dichromate, potassium dichromate, water-soluble alums including potassium chrome alum and sodium chrome alum, sodium hydroxide, potassium hydroxide, silver nitrate, ferric nitrate, and the like.

The aqueous solutions that serve as the ballasting liquid of this invention can be prepared by adding one or more of the salts to water, preferably with stirring. Heating before, during, and/or after stirring can be used to facilitate dissolution, e.g., heating from about 75 to about 200 F. The dissolving process is carried out for a length of'time sufficient to obtain the dissolution of sufficient salt to produce a liquid which contains substantially no suspended particles therein and which is in the required density range. Thereafter, the aqueous ballasting liquid is separated from any undissolved salts and is ready for immediate use as a ballasting liquid or for storage until needed.

Optionally, conventional bacteriostatic agents such as paraformaldehyde, glutaraldehyde, cresol, chlorinated phenols, and the like, and conventional corrosion inhibitors such as monolongchain alkyl, thriethoxylated polymethylene diamine, and the like can be employed to satisfy an over abundance of caution or to meet written specification requirements. Such materials are not necessary but can be added without detriment to the ballast liquid and its desired function.

EXAMPLE 850 pounds of potassium carbonate are dissolved in gallons of sweet water which contains substantially no dissolved halide salts by stirring the two together at ambient pressure and temperature for one-fourth hour. The resulting aqueous solution has a density of about 97 pounds per cubic foot, and a volume of about 131.5 gallons. The viscosity of this solution is 5 cps. at 75 F.

This aqueous liquid ballast fluid is then pumped into the ballast tank of aship in the same manner and with the same apparatus presently used to pump liquid ballast fluid that contains weighting particles dispersed therein. The aqueous ballast fluid of this invention, when emplaced in the ballast tanks of a ship, serves equally as well in stabliizing the ship as a ballast liquid of the same density which contains weighting particles dispersed therein. However, the ballast liquid of this invention need not be checked for undue settling out of weighting particles, as must generally be done with ballast liquid containing dispersed weighting particles.

Reasonable variations and modifications are possible within the scope of this disclosure without departing from the spirit and scope of this invention.

lclaim:

l. A method of ballasting a waterborne vessel having ballast tanks comprising introducing into said tanks an effective ballasting amount of a composition consisting essentially of water having dissolved therein at least one of carbonates, silicates, chromates, sulfates, hydroxides, nitrates, and nitrites of at least one of alkali metals, silver, lead, iron, cobalt, nickel, manganese, molybdenum, chromium, tungsten, vanadium, zirconium, and titanium, the amount of salt dissolved in the water being sufficient to give the composition a density of from about 75 to about pounds per cubic foot.

' 2. The method according to claim l wherein said salts are carbonates, silicates, chromates, sulfates, hydroxides, and nitrates of at least one of sodium, potassium, silver, lead, iron, cobalt, nickel, and chromium.

bonate.

4. The method according to claim 1 wherein said composition additionally contains effective amounts of at least one of bacteriostatic agent and corrosion inhibitor. 

2. The method according to claim 1 wherein said salts are carbonates, silicates, chromates, sulfates, hydroxides, and nitrates of at least one of sodium, potassium, silver, lead, iron, cobalt, nickel, and chromium.
 3. The method according to claim 1 wherein said salts are at least one of potassium carbonate, sodium carbonate, sodium silicate, potassium silicate, sodium chromate, potassium chromate, sodium dichromate, potassium dichromate, potassium chrome alum, sodium chrome alum, sodium hydroxide, potassium hydroxide, silver nitrate, ferric nitrate, and sodium carbonate.
 4. The method according to claim 1 wherein said composition additionally contains effective amounts of at least one of bacteriostatic agent and corrosion inhibitor. 